Leader pin



Nov. 13, 1934. E, BAUMBACH 1,980,174

LEADER PIN Filed July 30, 1932 MW Md m Arm 5 fzvpzwrmz ammM Patented Nov. 13, 1934 UNITED STATES PATENT OFFICE 2 Claims.

My invention relates to punch presses and has special reference to a means for insuring accurate positioning of leader pins in a die shoe.

More particularly, my invention relates to removable leader pins in a die shoe and means on both the pins and shoe for indicating, while the pins are being and after they have been inserted into the shoe, when the pins are in the identical position to that which they assumed before having been removed.

Leader pins are used in accurate punch-press work for guiding the punch holder to a perfect registration with the die shoe. As the pins are sometimes removed, and subsequently used again with the same punch-holder and die-shoe set, to have the pins arranged in precisely the same position in the die shoe as in previous assemblies is imperative to insure accurate alignment and registration of the punch and die.

Heretofore, the mechanic, for want of a better method, has, before the pins were removed from the shoe, punch-marked the two parts and effected registration of the two indexes when the two parts were again assembled. However, when the pins are being adjusted, before being forced home into the die shoe, the indexes which are to register are not close enough together to be judged accurately by the eye.

With my invention any error, while the pin is being driven into the die shoe, is readily discernible, and it is not necessary to drive the pin all the way into the shoe before an error shows.

An object of my invention is to provide removable leader pins so marked that after they have been removed from the die shoe they can be replaced in the shoe in identically the same position in which they were before being removed.

A further object of my invention is to provide removable leader pins having a means thereon for showing when the pins are in proper relation with respect to the die shoe when the pins are placed in position to be driven into the shoe, while the pins are being driven, and when they are in the shoe in operative position.

Still further objects of the invention will become evident from the description hereinafter outlined and from the drawing forming a part of this application, in which:

Figure 1 is a perspective view of a die set assembled in operative cooperation;

Fig. 2 is a sectional perspective view taken on the plane 2-2 in Fig. l; and

Fig. 3 is a perspective view of a leader pin.

Referring to the drawing in detail, the leader pin 10 is provided with an enlarged portion 11 at its base so that the pin can be readily inserted up to the enlarged portion, as shown in Fig. 2, through the hole 12 in the die shoe 13. The hole is just large enough to receive the enlarged portion 11 by a forced fit.

The aligning groove 14 on the leader pin is placed in coincidence with the aligning index 15 on the die shoe 13, as shown in Fig. 2, in preparation for pressing the leader pin into a forced fit with the die shoe, as shown in Fig. 1.

A further marking 16 is provided to indicate the position of the aligning means 14 with respect to the aligning index 15 after the pin has been driven into place and the bottom of the pin is flush with the bottom of the shoe.

It will be apparent to those skilled in the art that various modifications of my invention may be made without departing from the spirit and scope of this invention, and, therefore, I wish to be limited only by the prior art and to the extent of the scope of the appended claims.

I claim:

1. The combination with a die shoe of a removable round non-expansible leader pin having a drive fit in the shoe, said leader pin having an enlarged portion at its base, said die shoe having a round hole therein to receive the said enlarged portion, and being provided on its underside adjacent the hole with an aligning index, said die shoe having no part projecting within the cylindrical surface of the hole, and said enlarged portion being provided with a linear marking on its surface extending downwardly from the upper edge of said enlarged portion to the lower extremity of the pin parallel to the axis of the pin and having no part which enters the hole projecting beyond the cylindrical surface of the pin, said linear marking being capable of continuous registration with the index and visible while the pin is being forced into the shoe.

2. The combination with a die shoe of a removable round non-expansible leader pin having a drive fit in the shoe, said leader pin having an enlarged portion at its base, said die shoe having a round hole therein to receive the said enlarged portion, and being provided on its underside adjacent the hole with an aligning index, said die shoe having no part projecting within the cylindrical surface of the hole, and said enlarged portion being provided with a linear marking on its surface extending downwardly from the upper edge of said enlarged portion to the lower extremity of the pin parallel to the axis of the pin and having no part which enters the hole projecting beyond the cylindrical surface of the pin, said linear marking being capable of continuous registration with the index and visible while the pin is being forced into the shoe, the lower end of said pin being provided with an index registering with the lower portion of said linear marking which will register with the aligning index on the die shoe when the pin is pressed in the shoe in proper position.

EMIL A. BAUMBACI-I. 

